Adjustable cam means for winding machines



Jul 31, 1962 H. A. GEORGE 3,047,245

7 A ADJUSTABLE CAM MEANS FOR WINDING MACHINES Filed Jan. 20, 1960 2Sheets-Sheet 1 PRIOR ART INVENTOR l/a wnno A. 65026:

ATTORNEY July 31, 1962 H. A. GEORGE 3,047,245

ADJUSTABLE CAM MEANS FOR WINDING MACHINES Filed Jan. 20, 1960 2Sheets-Sheet 2 Illllllllll ATTORNEY United States This invention relatesto adjustable cam means and methods for making the same, and moreparticularly, to such apparatus and means for coil winding machines.

This application is a continuation in part of my prior application ofthe same title S.N. 420,031, filed March 31, 1954, now abandoned.

The use of cams is widespread in the winding of electrical coils, aswell as in the textile industry. In general, these cams control themotion of the wire guide which distributes the wire in a predeterminedpattern on the coil itself, as shown in FIGURE 8. Up until the presenttime, most cams were shaped specifically for the coil to be wound andthe shape or size of the coil could not be conveniently modified.Various devices have been used to overcome this diiiiculty by employinglevers or similar multiplying devices which generally introduced errorsin the traverse of the winding guide as compared to the original camsurface. Some of these errors result from the geometry of the amplifyingmembers, but additional errors arise from the mechanical difiicultiesinvolved in making all pivot points slack free. The cam of the presentinvention preserves the desirable feature of direct action on the wireguide without pivots, levers, or other error producing mechanisms. Atthe same time, it provides an opportunity for accurate control andcalibration of the length (or shape) of the traverse.

The adjustable cam of the present invention provides means for adjustingand modifying the throw of the cam without changing cams, and even formaking fine adjustments while the machine is running. This reducesset-up time tremendously and provides products which could not be madewith standard size cams.

Accordingly, a principal object of the present invention is to providenew and improved adjustable cam means.

Another object of the present invention is to provide new and improvedadjustable earn means for coil winding machines.

Another object of the present invention is to provide new and improvedcam means for providing a smoothly adjustable throw, thereby eliminatingthe need for a multiplicity of different cam sizes or-shapes.

Another object of the present invention is to provide new and improvedmeans for winding coils including means for adjusting the throw of thewire leading means without the removal of any parts.

Another object of the present invention is to provide new and improvedcoil winding apparatus including means for adjusting the cam throw ofthe apparatus while it is in operation.

Another object of the present invention is to provide new and improvedcoil winding apparatus comprising a cam for a smoothly adjustable throwat difierent planes along its axis, wire leading means adapted to bemoved by said cam, and means to move said cam along its axis to adjustsaid throw.

Another object of the invention is to provide new and improved means tomove a coil form and means to coordinate movement of the'coil formand'wire guide.

Another object of the invention is to provide new and improved means tomake special coils.

Another object of the invention is to provide new and improved means tomake progressive and bank wound coils.

Another object of the present invention is to provide new and improvedthree dimensional adjustable cam means.

These and other objects of the invention will be apparent from thefollowing specification and drawings of which:

FIGURE 1 is a perspective view of a conventional heart-shaped cam.

FIGURE 2 is a perspective view of a cam formed in accordance with thepresent invention.

FIGURE 3 is a plan view of the cam shown in the embodiment of FIGURE 2.

FIGURES 4 and 5 are sectional views of the cam shown in FIGURE 3 takenalong lines 4-4 and 55 respectively.

FIGURE 6 is a side view of the cam shown in FIG- URE 3.

FIGURE 7 is a plan view of apparatus for generating or manufacturing acam according to the present invention.

FIGURE 8 is a perspective schematic view showing coil winding apparatusconstructed in accordance with the present invention.

FIGURE 9 is a perspective view of another cam embodiment of theinvention for winding bank coils.

FIGURE 10 is a perspective view of another cam embodiment of theinvention designed for winding progressive universal coils.

FIGURE 1 illustrates a conventional heart shaped cam 1 commonly employedin some coil winding mechanisms. A cam with a constant displacement foreach degree of rotation is shown since this is the most used mot-ion.The symmetrical design provides for a linear traverse in of rotation anda traverse, also linear, in the opposite direction for the remaining180'. It should be noted that the shape of the follower 9' mechanism,affects the linearity of the resultant motion. This is shown by thedotted line 8 which traces the path of the follower as the cam rotates.The path is shown to meet the above conditions although the surface onthe cam would not. These comments are made to point out a fact whichotherwise might introduce confusion later.

The effective throw of the cam in FIGURE 1 is the diiference between theminimum and maximum dimensions of the cam, i.e. BA.

FIGURE 2 shows an embodiment of a cam of the present invention. It isheart shaped at one end 2' to provide a throw BA as in FIGURE 1. It iscircular at the other end 3 which provides zero throw since A=B. Betweenthe two ends it is smoothly tapering. Intermediate sections like 4 areheart shaped and have a corresponding intermediate throw. For instance,if the heart face 2 has a throw of .250" and the circular end 3: has athrow of .000", then all thro'ws between these limits are obtainable bymoving the cam along its axis. Intermediate throws dilfer in size butnot in characteristic shape.

The subject cam may be thought of as a multitude of flat cams as inFIGURE 1, assembled with the X axis in the same plane with a commonmounting hole. For the full advantage of this design the sum of A+B mustbe constant for all the unit cams. This stack of cams is so arrangedthat the throw as defined above increases progressively and uniformlyfrom one end of thestack to the other. In visualizing a single, unit soconstructed the individuallcams may be thought of as approachinginfinity in number so that the surface on which the follower rides issmooth and uniform. The resulting unit will act in the same manner asthecam described in FIGURE 1, but the throw of this cam will depend uponthe location of a spherical follower along the shaftway axis of the cam.By moving the follower or the cam along its axis the throw may bechanged at will. This approach should give a general concept of thiscam.

A second method of describing this cam of FIG. 2 would be to makecertain specifications about points and lines which lie on its surface.Intermediate points and the shape of the cam surface may be induced fromthese factors.

The following comments are actually based on the traverse of thefollower although for convenience we shall refer to the surface of thecam as though it were one and the same thing. (This condition could onlybe met if the follower were actually a point rather than a sphere withan appreciable radius.)

In FIGURE 3 the X axis is constructed so as to pass through the minimumand maximum dimensions of the heart face of the cam which are 180 apartby previous definition. The Y axis is originally placed at a 90 positionto the X axis, so as to intersect the X axis at the center of rotationof the cam. By previous definition it should be noted that A+B=A+B'. Itshould also be noted that with the Y axis in the 90 position A=B'. Ifthe Y axis is rotated clockwise so that it approaches X axis, A willdecrease uniformly with rotation until it equals A, while B willincrease accordingly to B, the fundamental relationships mentioned aboveremaining: i.e. A-i-B=A'+B'. While all of this discussion could properlyhave been applied to a single cam as in FIG- URE l, the subject cam is athree dimensional concept which meets these requirements at any planeperpendicular to its axis. It should be further stated that a sectionthrough the cam parallel to its axis on the line X-X will show a sectionwhich is a parallelogram as in FIG- URE 5, while a section taken throughthe axis YY' is a rectangle as in FIGURE 4. Any section taken on theline Y--Y as it rotates toward XX' is a transition from the rectangle tothe parallelogram in which the angle 0 FIG. 5, is constantly becomingmore acute. FIG- URE 6 is a left side view of FIGURE 3.

Another method of defining the shape of this cam may be by means ofdiscussing its method of generation. In FIGURE 7, the cam 10 is mountedon a spindle 11 such as in a lathe 19. A motor driven cutting tool suchas an end-mill 12 is mounted on a rotating table 13, the rotation ofthis table being linked to the spindle on which the cam is mountedthrough suitable worm 14, spur 15 gearing and change gears 11'. Thesolid lines show the position of the rotating end mill 12 at the 90 ormid point of the generating motion, while the upper and lower dottedpositions show the location of the end mill at the minimum and maximumtarverse of the generated cam. Suitable change gears 11 are used toachieve the desired traverse in 180 of cam generation. It should benoted that the end mill 12 which generates the surface of the cam ispreferably of the same radius as the sphere which is to be the camfollower. The center of the end mill traverses a path indicated by thedotted line 8, in FIGURE 1, while the cutting edge of the end millfollows the desired contour. curacy, the spindle 11 holding the cam 10and the axis of the cutter 13 must not only be parallel at the 90 point,but must lie in the same plane at all times.

It is further noted that in addition to the concepts mentioned above,the apparatus shown in FIGURE 7 suggests the following:

If the center of rotation 13' of the table 13 on which the cutting toolis attached coincides with the plane of either face of the cam as shownin FIG. 17, then that face is circular and has a zero throw. If thispivot point falls between the two faces of the cam, then the resultingunit has a O or null point at a corresponding plane. On each side ofthis point lie planes which produce throws equal but opposite to eachother and progressively larger. If the pivot point falls outside of thecam, then no zero throw exists and the resulting cam provides adjustmentbetween the limits available at each heart shaped face.

To produce cams of maximum ac Referring to FIGURE 8, it is generalpractice in machines of this type to make the movement or motion of thewinding finger positive in both directions. This is accomplished byusing two points of contact of the cam follower 20 on the cam, ratherthan one. In FIG- URE 1, this second point would be at the apex of thecam and is always located 180 from the first point. In other words, thetwo points of contact are in a line which passes through the center ofthe shaft on which the cam is mounted. The distance between these twofollowers is represented by A-l-B and is therefore constant. The cam ofthe present design is of such shape that A+B is constant for any twopoints on its surface lying in the same plane through the shaftway axis,and, therefore, no new compensating device need be introduced. To adapta standard machine to this unit requires only that a method of movingthe cam shaft along its axis be provided. A suitable method ofcalibration is also desirable.

FIGURE 8 shows a schematic of such a coil winding machine design. Thewire 33 is fed onto the coil form 34. The wire leading arm 35 is mountedon shaft 36 which is actuated axially by the action of cam 37, and camfollower yoke 20, to provide the desired coil shape. The coil form 34 isadapted to be rotated by spindle 23. In certain applications, thespindle 23 is also moved axially by rack 76, for winding certain typecoils such as, for example, progressive universal or bank wound typecoils.

Power is applied by driving means 23' which drives spindle 23", spindle23 is connected to spindle 23" by spline connectors to permit axialmovement of the spindle 23 which is mounted on rack 76 by bracket 77,and collar 78.

Gears 50 and 51 are change gears used to secure satisfactory turns perlayer or suitable cross over pattern for the winding of a specific coil,50, being the driver gear which is mounted on a drive shaft 22 driventhrough a worm gear arrangement or other means such as right angle drive52, 52' by the spindle 23. 53 is a bracket holding an elevated idlergear 54 which may be placed at a convenient position for linking the twochange gears, 50 and 51. 55 is the cam shaft which carries the drivengear 51 on one end and the adjustable cam 37 on the other. The shaft 55rotates in bushing 56 which is prevented from rotating by a key 57 orsimilar device. 58 is a gear which has internal threads in the hub tofit similar threads 59 on bushing 56. It should be noted that gear 58 issecured against movement along its axis by solidly mounted bracket 60.Bushing 56 and shaft 55 have collars or shoulders (not shown) so thatwhen bushing 56 is moved axially the shaft 55 is also moved axially.Thus, rotation of gear 58 results in the axial movement of the entireassembly consisting of gear 51, shaft 55, hub 56 and cam 37.

This brings the desired area of the cam into contact with the camfollower points on yoke 20. Idler gear 54 has teeth of sufficient lengththat change gear 51 remains in mesh with it regardless of the positionof the cam shaft 55. To provide conventional adjustment and calibrationfor this device, shaft 62 has a small pinion gear 63 which engages gear58 and a worm 64, and suitable means of attaching a wrench or knob 65,by which the actual adjustment is made. The worm 64 engages a gear 66 onvertical shaft 67 which carries an indicating pointer 68 on its upperend. The gear ratios are preferably so chosen that one revolution of theindicating hand covers the full range of cam adjustment. The hand issecured in such a fashion that its position in relation to the shaft canbe altered for calibration. When it is desired to move the coil form 34axially for progressive universal or bank wound coils, knob 79 is pushedin thereby connecting rack 76 to the driving source via gear 75 whichengages the rack gear 74, idler 72 on bracket 73, gears 71 and 70 todriver spindle 23"". Gears 71 and 74 are change gears, which may bechanged to provide the desired rack movement.

Among the advantages of an adjustable cam throw are economy ofequipment, ease of setup, flexibility and This particular design hasother advanconvenience. tages and applications beyond those available inother equipment designed for similar purposes.

Speed of operati0n.-'I'he yoke and follower design used with this camand shown in FIGURE 8 represents the very minimum weight in thereciprocating parts. In fact, no additional reciprocating parts havebeen added to utilize this cam and soits use does not curtail theoperating speed.

Direct action.The design of this cam permits continued use of the verydesirable feature of having the cam act directly; i.e. rather thanthrough levers or pivots. Mechanisms employing pivot joints or slidingmembers depend on their fit for accurate results. In this design theaccuracy of the cam surface alone determines the accuracy of themovement of the wire guide.

Low c0st.--Previously accuracy and speed mentioned above could beobtained only by using cams of a specified and unalterable throw. Ifsuch cams are to be manufactured with reasonable accuracy their cost isnot inconsiderable and a group of cams to give a continuous range equalto one of the cams of the adjustable type would cost a great deal morethan the single cam.

C0nvenience.-The convenience of this design is manifold. In determininga satisfactory coil setup, previous procedure involved the manufactureor purchase of a cam of definite specified size and shape. Once this camwas procured experience might show that a cam slightly different in sizeor shape should be tried. The attendant delays in securing a cam to thenew specifications often proved considerable. With this design, thesecompensations can be made immediately.

An additional convenience is that the necessity of removing one cam andinstalling a substitute is eliminated. Since the cam follower spacingmight vary from cam to cam this adjustment is also eliminated by the newdesign.

Self-centering feature.A cam of the design mentioned above not onlyprovides for an accurate and continuous adjustment of the length oftraverse of the winding button, but also makes this adjustment of equaleffect at each end of the stroke. When this stroke of the cam isadjusted, therefore, the coil continues to be wound in the same area.With bobbins (flanged fors) this means that the cam adjustment can beused to secure even buildup to each flange.

Adaptability.While the specific design described is basically a linear,constant Velocity, constant displacement unit, this need not be alimiting specification in the design. Non-linear cams may be constructedwhich likewise have the advantage of adjustment using the mechanismdescribed herein.

Once the general structure of the basic cam is understood and amechanism provided to utilize the adjustable features, variations anddeviations from the cam form may be made for specific applications. Inthese cases certain features which may not be needed for the problem athand may be sacrificed in order to secure further advantages. Two suchcam forms are described below, in connection with FIGS. 9 and 10. Inboth of these illustrations the condition A+B equals A'-]-B' issacrificed. This means that a spring loading on the left hand followerin FIGURE 8 must be used. The right hand follower alone determines themotion of the winding wire guide. (This spring is often used with theoriginal cam design to eliminate errors due to wear of the machine orother factors.)

In the winding of the so-called bank-wound coils successive turns arewound on top of the preceding one running up a bank at approximately a60 angle from the core axis. Each of these turns is thought of asbelonging to a separate layer and thus, a six layer bank wound coilwould have six such turns and the seventh turn would be preceded by arapid excursion down the slope of the bank to the core on which the coilis wound. Starting with the seventh turn, the process is repeated. Theproblem of displacement of the rapid return to secure suitable nestingof the turns does not affect the cam design and is not a part of thisdescription. In winding a bank wound coil it is customary to depend pponthe cam to produce the basic motion of the winding finger and at thesame time a suitable means of moving the coil along its axis must beprovided so that when the winding finger has returned for turn seven tothe place it occupied for turn one, then the coil will have beendisplaced one wire diameter, the combination of these two motionsproviding the desired pattern.

FIGURE 9 illustrates the approximate shape of a cam for this purpose.Since the placement of these turns is very critical, the amount of throwin the cam must be adjusted very closely and generally must bedetermined by trial. If a cam is made of an appearance similar to FIG.9, in which the one end 30 is a circle and the opposite end 31 is a camof the indicated spiral shape, then this adjustment can be made usingthe mechanism we have described in FIG. 8.

Referring to FIG. 10, a second cam variation is designed for the more"accurate winding of the so-called progressive-universal coil. Thiswinding is produced by having a wire guide place the wire in a path verysimilar to that used for the more common lattice, or universal coils,while at the same time the coil form is moved along its axis at auniform slow rate. The winding of lattice patterns has been developeduntil 'a very stable pattern has been achieved. This results from acareful balancing of the various factors such as wire size, cam throw,and coil diameter. When a progressive universal coil is wound, thesecritical calculations are upset since the rate of traverse of theconstant progression is added to the rate of traverse produced by thesame in one direction of its throw and is subtracted from it in theother direction. It is possible to displace the nodes on a cam so thatthey are not 180 apart, thus altering the rate of traverse in bothdirections. In this manner, it is possible to wind a progressiveuniversal coil of a quality equally as good mechanically as can beachieved with a simple universal pattern. The increased mechanicalquality results in more uniform and stable electrical characteristicsand this change materially reduces the distributed electrical capacityof the coil.

In designing an adjustable cam for such purpose, adjustment of thedisplacement (in degrees) rather than in distance is desired. In otherwords, such a cam has a constant amount of throw. One heart face 32 ofthis cam, FIG. 10, would have the maximum and minimum dimension; i.e.A+B dimensions, 180 apart. On the other face 42 these two dimensionswill be separated by less than 180, generally about as shown in FIGURE10. Using the mechanism described for adjustment this cam will provideany degree of displacement necessary to compensate for the progressionof the coil. Coils with very slow progression will be wound near theface while coils with the most rapid progression will be wound near the90 face.

I claim:

1. Coil winding means comprising a movable rack, a spindle rotatablymounted on said rack, drive means connected to rotate said spindle,movable gear means for connecting said drive means to said rack, a coilform on said spindle, a cam shaft mounted perpendicular to said rack andsaid spindle, a cam on said cam shaft, cam follower means mountedadjacent said cam and adapted to be oscillated by said cam, wire guidemeans connected to said cam follower means and extending over said coilform, a gear train connecting said driven spindle to said cam shaftincluding change gears for adjusting gear ratio, and means to move saidcam shaft and cam axially to move said cam surface relative said camfollower.

2. Apparatus as in claim 1 wherein said last means comprises a hubmounting said cam shaft, said hub being movable axially with said camshaft and having external threads thereon and an adjusting gear havinginternal threads mounted on said external threads, knob means connectedto rotate said gear to move said cam shaft axially, and indicator meansconnected to said knob means.

3. Coil winding means comprising a movable rack, a spindle mounted onsaid rack, drive means connected to rotate said spindle, movable gearmeans for connecting;

said drive means to said rack, a coil form on said spindle, a cam shaftmounted perpendicular to said rack and said spindle, a cam on said camshaft, cam follower means mounted adjacent said cam and adapted to 'beoscillated by said cam, wire guide means connected to said cam followermeans and extending over said coil form, a gear train connecting saiddriven spindle to said cam shaft including change gears for adjustinggear ratio, and means i to move said cam shaft and cam'axially to movesaid cam surface relative said cam follower, comprising a hub mountingsaid cam shaft, said hub being movable axially and having externalthreads thereon and a gear having internal threads mounted on saidexternal threads and means 605,984 Whyte June 21, 1898 1,927,547 GordonSept. 19, 1933 2,305,085 Jacob et a1. Dec. 15, 1942 2,771,250 IcenbiceNov. 20, 1956 FOREIGN PATENTS 21,686 Great Britain Sept. 23, 1910110,705 Australia Oct. 10, 1928 412,315 Italy Nov. 26, 1945

